1. Technical Field
This invention relates generally to electronic devices having multiple sections, with electronic components in each section, where power is transferred between the sections, and more specifically to a multiple section electronic device having an adaptive circuit for maximizing the efficiency of power transfer between the electrical components in each section.
2. Background Art
Electronic devices, like mobile telephones for instance, have advanced a long way in the past twenty years. Using the mobile telephone as an example, in only a short time, it has made the transformation from a large, bulky, heavy, expensive device to a device so slim, sleek, light and affordable that everyone can keep one in a shirt pocket.
Continuing the example, the mobile telephone of the late eighties was a device about the size of a shoe, with a large antenna coming out of the side. It had a battery pack the size of a fishing tackle box, and a bulky cord running between the battery pack and phone. Today, some mobile telephones are less than a quarter inch in thickness, weigh less than 5 ounces, and have internal antennae that are not even visible by the user. Modem mobile telephones even include sleek, aesthetic mechanical features as well. Some flip open like a clamshell, some swivel open like the hands of a clock, and others slide open. Indeed, phones with such mechanical features make the unopened smaller and easier to carry when not in use, yet make the phone more comfortable and more like a traditional phone when in use.
Such sophisticated mechanical opening and closing mechanisms, considered to be fashionable features by many, can create problems for the engineers and designers who make the mobile telephone. The mobile telephones of today are so small, that electrical components must be located in both sections of the phone. A display driver and radio frequency (RF) circuit may be in one section of the phone, while a microprocessor and voice encoder may be in the other section. Sophisticated electrical connections, including flexible conductors, are needed to transfer power back and forth between the sections. As the processors and RF circuits operate at high frequencies, this “electrical joint” can sometimes make the phone less efficient.
For example, when the microprocessor attempts to send high frequency messages to the RF circuitry, the electrical joint may inadvertently cause some of the energy to be dispersed. Where the phone has a metal surface, some of this power may get inadvertently coupled to the surface and become small surface or eddy currents. When the transferred energy becomes a surface current, it can't be used, for example, to transmit a call to a tower. The net result is decreased battery life and inconvenience for the user, as the user can't get as much talk time out of the phone.
One prior art solution to this problem is that of making a mobile telephone without a mechanical connection, and thus without an electrical joint. Some manufacturers do indeed offer these “candy bar” phones that do not flip, swivel or slide. The problem with this solution is that people enjoy the sophisticated mechanical features and thus are willing to even pay a premium to have them.
There is thus a need for an improved electronic device having a mechanical connection between sections that improves the efficiency of power transfer between the sections.
Skilled artisans will appreciate that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions of some of the elements in the figures may be exaggerated relative to other elements to help to improve understanding of embodiments of the present invention.